Diffractive optical element, method of producing a diffractive optical element and laser component
A diffractive optical element includes a carrier and a plurality of nano- or micro-scale rods arranged above a top side of the carrier, wherein the rods are arranged parallel to one another in a regular grid arrangement. A method of producing a diffractive optical element includes providing a carrier and epitaxially growing a plurality of mutually parallel nano- or micro-scale rods in a regular gird arrangement above a top side of the carrier.
1. A diffractive optical element comprising a carrier and a plurality of nano- or micro-scale rods arranged above a top side of the carrier, wherein the rods 1) are arranged parallel to one another in a regular grid arrangement, and 2) comprise a first group of the rods and a second group of the rods, and
the rods of the second group comprise a greater length than the rods of the first group.
2. The diffractive optical element according to claim 1 , wherein the rods comprise gallium nitride.
3. The diffractive optical element according to claim 1 , wherein the rods each comprise a hexagonal cross section.
4. The diffractive optical element according to claim 1 , wherein the carrier is formed as a sapphire wafer.
5. The diffractive optical element according to claim 1 , wherein the rods are covered by a protective layer.
6. The diffractive optical element according to claim 5 , wherein the protective layer comprises silicon dioxide, silicon nitride, a silicone, a phosphate glass, an epoxy or polymethyl methacrylate.
7. The diffractive optical element according to claim 1 , wherein neighboring rods comprise a distance from one another of 0.5 μm to 5 μm.
8. The diffractive optical element according to claim 1 , wherein the rods each comprise a length of 0.5 μm to 50 μm.
9. The diffractive optical element according to claim 1 , wherein the rods comprise an average roughness R a of less than 0.5 nm.
10. A method of producing a diffractive optical element comprising:
providing a carrier; and
epitaxially growing a plurality of mutually parallel nano- or micro-scale rods in a regular grid arrangement above a top side of the carrier.
11. The method according to claim 10 , further comprising:
forming a mask structure comprising a plurality of openings arranged in a regular grid arrangement above a top side of the carrier,
wherein the rods are grown above the openings of the mask structure.
12. The method according to claim 11 , wherein the mask structure is formed from a silicon oxide.
13. The method according to claim 10 ,
wherein the carrier is provided with a crystalline buffer layer arranged above its top side, and
the rods are grown above the buffer layer.
14. The method according to claim 13 , wherein the buffer layer comprises gallium nitride or aluminum nitride.
15. The method according to claim 10 , further comprising:
covering a first group of the rods, wherein a second group of the rods is not covered; and
continuing the epitaxial growth of the rods of the second group.
16. The method according to claim 10 , further comprising covering the rods with a protective layer.
17. The method according to claim 16 , wherein the protective layer is applied by a cathode sputtering method.
18. A laser component comprising a laser light source and a diffractive optical element comprising a carrier and a plurality of nano- or micro-scale rods arranged above a top side of the carrier, wherein the rods 1) are arranged parallel to one another in a regular grid arrangement, and 2) comprise a first group of the rods and a second group of the rods, and
the rods of the second group comprise a greater length than the rods of the first group, arranged in the light path of the laser light source.